The aim of this research is to obtain basic information on the respiratory chain enzyme system of mitochondrial inner membrane enabling conclusions on sequence, action and mechanisms of electron and coupled energy transfer as well as the role of the membrane in these processes, mainly by the methods of sequential fragmentation, systematic reconstitution, identification of the enzyme location (in the 3- dimensional sense), and related physico-chemical techniques. Among others, the resolved enzymes and components are first purified (crystallized, if possible) and then rigorously characterized by various physico-chemical and enzymic techniques. The effect of chemical (as well as physical) modification of the resolved components is studied by the criterion of reconstitution. An ultimate goal in our first phase, not necessarily the eventual goal, is reconstitution of the complete bioenergetic apparatus with all functional manifestations of the mitochondrion. It must be pointed out that this application (which differs from another project) emphasizes on and deals with aspects on cytochrome- containing parts of the respiratory chain including: (1) cleavage of the cytochrome b-c segment, (2) studies of cytochrome oxidase, (3) molecular mechanism of electron transport and (4) reconstitution of Site 2 and Site 3 phosphorylation.